Osteoarthritis (OA) affects roughly 31 million Americans. Over 70% of wrist OA cases are a form of degenerative arthritis associated with severe pain. Treatment for severe wrist OA commonly involves motion-preserving surgical salvage procedures. One of the most common of these procedures, proximal row carpectomy (PRC), involves removal of the entire proximal row of carpal bones, shortening the forearm-to-hand length. This procedure is successful in relieving pain and improving function relative to an untreated wrist. However, compared to a healthy wrist, PRC often yields decreased range of motion and loss of grip strength, the latter of which is particularly devastating. The cause for loss of grip strength following surgical salvage procedures is not well understood. The objective of this study is to test the clinical assumption that loss of grip strength following PRC is a result of “slackening” of the muscle-tendon unit. The idea of muscle-tendon unit “slackening” arises because the PRC procedure shortens the carpus, decreasing the distance between the origin and insertion points of muscle-tendon units that cross the wrist, but concomitant surgical shortening of muscle-tendon units is not performed. Thus, post-operative wrist muscle-tendon lengths are thought to be relatively long, or “slack”, following PRC. Though human skeletal muscle adaption to chronic limb length change is poorly understood, the classic immobilization studies of the 1970’s and 80’s and more recent surgical tensioning studies in animal models  inform our central hypothesis that following the chronic limb shortening imposed by PRC, muscle-tendon units do adapt, predominantly as a shortening of muscle fascicle length through serial sarcomere deletion. The rationale behind this proposed study is that an important first step in determining what causes loss of grip strength following PRC is understanding how shortening the carpus alters force-generating parameters of muscle-tendon units that provide strength to the wrist and hand.
|Effective start/end date||11/1/18 → 10/31/20|
- DeLuca Foundation, Inc. (letter 9/5/18)